With so many new clubs, the NASL realigned into a six-division format while expanding the playoffs to include 16 teams. The new alignment was a direct copy of the NFL's setup, as the new three-team conferences were called the 'American Soccer Conference' and the 'National Soccer Conference', respectively. Each conference had East, Central and West divisions as well.[16]

The top two teams in each division would quality for the playoffs. The other spots would go to the next best two teams in the conference, regardless of division. The top three seeds went to the division winners, seeds 4-6 went to the second place teams and the last two seeds were known as 'wild-cards' – another nod to the NFL. The winners of each successive round would be reseeded within the conference. The first round and the Soccer Bowl were single games, while the conference semifinals and championships were two-game series. As in the 1977 playoffs, if both teams were tied at one win apiece at the conclusion of Game 2, there would be a 30-minute sudden-death mini-game and a shootout if necessary.[17]

The Cosmos would set records for most wins and points in an NASL season, thanks to their 24-6 regular-season mark (shared with the Vancouver Whitecaps) and 212 points. The Cosmos beat the Ft. Lauderdale Strikers 7-0 on opening day[18] and never looked back, scoring 88 times while losing just three games in regulation. Giorgio Chinaglia scored 34 goals and 79 points, setting league records in the process. He did not win regular season MVP honors, however. That award went to New England's Mike Flanagan, who scored 30 goals and 68 points while leading the Tea Men to an unlikely ASC East title. At the age of 36, Alan Hinton of Vancouver set a league record of his own with 30 assists.[19]

After the season Colorado would move to Atlanta,[24] while Oakland would move to Edmonton just two months before the start of the 1979 NASL season.[25] The Stompers had drawn over 32,000 for their opening game at the Oakland Coliseum,[26] but were drawing crowds under 10,000 by the end of the season. The Caribous had the worst record in the league and only drew one crowd bigger than 10,000 the entire year.

Conference Semifinals

In 1978, if a playoff series was tied after two games, a 30 minute, golden goal, mini-game was played. If neither team scored in the mini-game, they would move on to a shoot-out to determine a series winner. *Teams were re-seeded for the Conference Semifinals based on regular season point totals. This affected only one of the four series; Tampa Bay versus San Diego.[27]